The need to carry out the connection between the Terminal of the airport and aircraft arose during the first half of the 20th century, with the appearance of the first commercial airlines. The design of boarding bridges has undergone changes over time and technological improvements have been made which respond to new customer expectations and which have taken root and extended in new designs.
Currently known bridges are formed by a rotating structure known as rotunda connected to the facade of the Terminal where the passengers board and disembark; a rotunda support structure called column, a tunnel formed by a telescopic structure which allows modifying the length of the bridge according to the distance between the Terminal and the airplane boarding door; an elevation system also formed by a telescopic structure on which the tunnel is supported and which allows modifying its height and adapting to the airplane door level, a running system on which the elevation system is supported and which allows the movement of the bridge on the airport platform, a rotating structure called cabin which can be used as a link between the bridge and the airplane, a circular structure called cabin rotunda on which the cabin rotates; and stairs usually located at the end of the bridge closest to the airplane which allow accessing the bridge from the airport platform.
Conventional telescopic boarding bridges for an airport require a system which allows transmitting both the electric energy and the control signals to all the used systems. The electric power generally goes from the connection, normally located in the column, which is the fixed part, to the electric cabinet located in the cabin rotunda. The energy is distributed from there to all the electric devices located in the different parts of the bridge, both fixed and mobile.
Transmission systems based on using mobile cables have been used up until now in order to fulfill this purpose.
One of these systems is formed by a beam secured by several angle bars to the upper part of one of the sides of the outer telescopic tunnel of the bridge. This beam has at its lower part a rail over which the carriages holding the cables slide, such that when the bridge is extended the cables are extended on the sliding carriages, which are equidistant from each other, whereas when the machine is retracted, the carriages move closer together such that the cables hang forming tails on the side of the bridge, which creates an unaesthetic effect in addition to interfering with other elements of the bridge.
Another of the systems used consists of a cable holder chain causing the movement of the cables during the telescopic movement of the tunnels of the bridge, taking them through a standard link chain, which is fixed at one end to the outer tunnel and at the other end to the inner tunnel. This chain is supported on a tray located on the lower part of the tunnels.
Both solutions subject the cables to continuous stresses, causing breaks of the conductor and/or the insulator which end up rendering the bridge inoperative over time. Furthermore they are very large systems, which involves a problem from the aesthetic and assembly point of view.
A transmission system for efficiently and comfortably transmitting energy and data from a connection point to all parts of the bridge, preventing the drawbacks existing in the previous systems of the state of the art, was therefore desirable.